I have purchased the metal and linear motion materials so I am kind of limited with any modifications I can make now.
For the Z-axis, I am making it out of 0.5" steel plate and there is less than a 6" section of the plate that is past the fulcrum (the bottom bearing block). I am having difficulty seeing how this will flex. I am only using this machine for aluminum and woods and I will not be running it very hard most likely.
For the spacer tubes. They are 1/4" steel. I have seen other CNC's like Wade'O's where they machined the tube surface (for the gantry in his case). The tubes are quite small on my CNC so will they have a significant risk of warping? I don't have any experience milling steel tube but I find it hard to picture these tubes warping much.
I'm not fully sure what you mean with the Z axis spacers but I wanted to avoid them but couldn't due to motor clearance as the plate would have impacted the motor. The nut was also at a height that the bearing blocks needed spacers or it would have collided with the Z plate.
The way I am imagining milling the X-axis plates flat is by assembling the base of the frame completely and then putting everything firmly on a mill and milling the surfaces flat with a fly cutter or something. Ideally milling the plates in one go (depending on the clearance the shop's mill has). I am trying to get 0.5" plates instead of the 0.25" ones on my last model.
For the base plate (X-axis plate) : I can't afford a $300-$400 aluminum plate (I may replace it in the future with a decent aluminum one). I live in Canada so shipping and our currency is not making if simple to find affordable aluminum plates. I am going to try to use a hot rolled steel plate (20" x 24" x 0.5") and use a fly cutter on a mill to flatten the surfaces. I will probably finish the surfaces by hand after fly cutting them.
Since I am machining the surface of the x-axis rail mounts once the base if fully assembled, will I still risk having the rails bind? I plan to bolt all the plates together and use thread lock to prevent them from coming loose.
And could you send me a picture of roll pins being used? I have never seen them before and still don't know what exactly they are.
I appreciate all the help again. I am going to have to keep the gantry as is due to the fact that a single upright would not allow the X-axis table to move very far as the upright would be right in the way (unless i'm picturing it wrong).